Synthesis of Biodiesel from Waste Cooking Oil by Using Seashells as Catalyst

The basic aim of this research is to study the suitable conditions of the biodiesel by using waste refined cooking oil as a preliminary material with heat-treated seashells at 500°C, 800°C, and 1000°C as heterogeneous catalysts. It recorded at 800 °C a high level of CaO as catalyst 90.89 % under the following reaction conditions: catalyst is 0.5 g, temperature at 80 °C, reaction duration is 180 minutes, and the oil-to-alcohol ratio is 10:20%. The impact of energizing temperature on transesterification processes in the range of 500°C–1000°C proved that the calcination temperature at 800 °C of seashell-derived material raised biodiesel to 97% due to active sites on catalyst surfaces, converting rate linearly in comparison to other catalysts, and this tends to reduce the cost of purification procedures of biodiesel. It has been proved that the catalyst at 800°C possesses a density at 40°C of 0.850 g /cm3, an acid value of 0.6 mg KOH/g oil, a viscosity of 4.9 mm2/s, and a flash point of 165°C. It also contains high catalytic activity in the transesterification process of wasted cooking oil (WCO) for optimizing biodiesel characteristics in the future. As a result, the catalyst demonstrated high action in the transesterification effect. Scanning Electron Microscopy (SEM) illustrates calcined waste shells are irregular in shape, which means small, minute grains of pores accumulate, providing a large area of surface. Furthermore, the physical characteristics of CaO catalysts at 800 °C showed Brunauer- Emmett-Teller (BET) a significant surface area of 76.1888 m2/g and pore volume of 2.6539 cm3/g is considerably greater than other catalysts at temperatures of 500 °C–1000 °C. X-ray diffraction (XRD) data analysis demonstrate the main constituent of seashells is CaCO3, indicated by the diffraction peak at 2𝜃 approximately 28.48∘. However, carbon dioxide CO2 changes when the calcination temperature at 800 °C it transforms CaCO3 completely into CaO, which is the main component of the calcined catalyst. The CaO catalyst's well-crystallized structure is defined by the narrow, high-intensity peaks of catalyst. Eventually, the heterogeneous catalyst led to a significant rise in the active sites.

Esraa Mohamed Musa and Norah A. Alsaiari